As I write this, I'm currently on the Amtrak Acela Express train from Providence, R.I., to New York City. Joining me on this journey is the Verizon Jetpack, a 4G LTE MiFi (made by Novatel Wireless, model 4620L) unit that acts as a bridge between my Wi-Fi client (a MacBook Pro) and the 4G LTE wireless service offered by Verizon Wireless.

About the size of a deck of playing cards, the Jetpack can support up to 10 different Wi-Fi connections over the 4G LTE connection (over 3G it drops to only five supported devices). This lets you easily share the connection with co-workers or family members while traveling -- for example, in locations where Wi-Fi might be available, but expensive (hotel rooms) or with bad service (bad hotel rooms).

The Jetpack powers up quite easily, and if 4G LTE service is available, it will quickly connect and makes itself available to users. Connecting to the Jetpack is done via WPA2, so guard the unit's password carefully (you can change it, of course, if you want).

The device has a very nice graphical display on the top, giving you information like how many bars of service you have, whether you're connected via 4G or 3G, how many users are currently connected, and battery life indicator. My only complaint is that to save power the display goes dark after a brief period -- if you want to constantly monitor your connection, you have to keep pressing the power button. Another warning -- while the speeds are great with 4G LTE, you have to be careful to make sure you don't go over your allotted data allowances.

Now for the train test. Amtrak does offer its customers free Wi-Fi access, but the connection from the Wi-Fi router to the Internet isn't 4G, as far as I could tell.

During my trip I wrote three blog posts (including uploading photos), checked email and browsed the Web. When the service dropped to 3G, it got more difficult to access some sites or perform uploads. The data speeds also seemed to slow the faster the train went -- we got our best coverage and speeds when the train was moving slowly or at a station.

12:10 p.m. First drop from 4G to 3G speeds. Returns to 4G coverage/connection at 12:20 p.m.

12:22 p.m. Spoke too soon -- down again to 3G. This would happen on and off for the next 12 minutes or so.

12:34 p.m. Time for a speed test -- 4.32Mbps down, 0.30Mbps up -- train slows down due to congestion in Groton, Conn. Stays on bridge for several minutes, allowing me to upload blog posts and photos without worry.

12:57 p.m. The train is moving quickly, I have three bars of 4G coverage. Test shows 1.07Mbps down, 1.33Mbps up -- that's never fun, when uploads are faster than downloads.

12:58 p.m. Back to 3G -- from here until 1:30 p.m., we get spotty coverage, but it does seem to stay at 4G for the rest of the trip.

2:02 p.m. Still on 4G, but speeds aren't really that great. Finished trying to write blog posts, just checking email and surfing the Internet -- no heavy lifting.

2:19 p.m. Turned off everything, switched to see if Spotify could stream (mainly because of the annoying conversation going on behind me). A couple of glitches listening to music, but not horrible.

2:32 p.m. Trying Netflix quickly before the train arrives. Sadly, Netflix needs Silverlight plugin to view over Firefox browser, spend rest of the trip downloading plugin (getting about 250KBps, but dropping at times to about 70KBps.)

2:41 p.m. Yes! It works! Sort of -- got 10 seconds of video before it stalled.

3:22 p.m. Checked into the hotel, in the room, checking Internet speeds. Four bars on the 21st floor in midtown Manhattan. Wow. 15.6Mbps download, 5.03Mbps. There's no place like New York. Time to get some real work done.

Grade: 4.5 stars (out of five)

Shaw can be reached at kshaw@nww.com. Reach him on Twitter: @shawkeith.